The use of laser devices to undertake various fabrication, cutting, shaping, inspecting and other manufacturing and related operations is realizing greatly increased popularity in various industries throughout the world. As many uses for laser devices include repetitious manufacturing operations which preferably incorporate manipulator devices such as robots and the like to deliver the laser to a particular point in space or onto a particular object, it is often necessary to deliver a laser beam along and/or through various parts of a moving laser beam delivery system. The beam delivery system may take the form of a dynamic manipulator device, such as a robotic device having one or more rotating joints. In order to accomplish the transmission of the laser beam through the laser beam delivery system, it is often necessary to route the laser beam with various moveable and non-moveable optic structures, mirror packages and the like. Where a laser beam delivery system includes one or more rotating joints which carry rotatable laser optics, various translational and angular position errors of such laser beam can find their way into the system.
Position errors of a laser beam can be the cause of variable power levels, power loss, poor beam quality and various beam locational errors which cause inefficiencies and unreliability of the laser at its output location. Obviously, such inefficiencies and position inaccuracies are unacceptable in today's demanding applications. Consequently, it is critical to the efficient and accurate delivery of a laser beam to minimize the translational and angular errors of the laser beam as it is directed through its delivery system by various laser beam optics, mirror packages or the like.
One method which has been used in the industry to correct deviations of a laser beam along its delivery path is to cover the end of a portion of the laser beam delivery system with a diffusing device having a set of intersecting cross hairs drawn or etched onto one side thereof. Appropriate optics of the laser beam delivery system are thereafter adjusted to appropriately center the laser beam in the cross hairs, which preferably are located at the center of that particular portion of the laser beam delivery system. While this technique can be used to generally center the laser beam within the delivery system, its accuracy is not reliable and it is not useful in correcting for angular deviations of the laser beam. Moreover, this technique is quite inconvenient to implement in applications where such laser beam delivery system includes one or more rotating joints and one or more rotatable laser optics or mirror packages to guide the beam therethrough.
An alignment tool was also made by Spectra-Physics Inc. of San Jose, Calif. for correcting laser beam rotational errors at moving joints of laser beam delivery systems. The Spectra-Physics tool, however, required disassembling the beam delivery system and performing alignment as the system was being rebuilt. In particular, the Spectra-Physics tool comprised a focusing lens which received the laser beam and collimated the beam to a point on a screen spaced from such collimating lens at the focal length thereof. In this way, the angular errors of the beam would be isolated by the collimating effect of the lens, and any angular error could be adjusted out of the laser beam by monitoring the movement of the beam on the screen and making appropriate adjustments to the laser optics. However, the Spectra-Physics tool was large, limited solely to the removal of angular beam errors, and was difficult to use in that it required disassembly of the beam delivery system to perform the alignment procedures.
A laser measurement system is shown in U.S. Pat. No. 4,483,618 which issued to M. Hamar on Nov. 20, 1984. However, the Hamar measurement system utilizes a plurality of mirrors to place a virtual image of a sensing device at an otherwise inaccessible physical point for the purpose of accurately determining the position of that point relative to another predetermined physical point. In this way, the system is described with respect to an apparatus for measuring distances such as for locating a point on a machine part, or locating a point on a position scale. Consequently, the Hamar '618 patent fails to address the problem of aligning the angular and translational position of a laser beam delivery system containing a rotating joint and one or more rotatable laser optics. Similarly, U.S. Pat. No. 4,566,202, which issued to M. Hamar on Jan. 28, 1986, describes a tool containing a laser source which is used to align a rotatable part about the mechanical axis of a tool. Again, this laser apparatus fails to address the need for an alignment tool for aligning both angular and translational position of a laser beam in a laser beam delivery system.
As a result, heretofore there has not been available in the industry a relatively simple, easy to use, compact, laser alignment tool which provides for efficient alignment of both angular and translational position errors of a laser beam. U.S. Pat. No. 4,618,759, which issued to G. Muller et al. on Oct. 21, 1986, sets forth an arrangement for compensating for offset and angular errors of a laser utilized in a processing or measuring machine. However, the beam position control arrangement set forth in Muller et al. is designed to determine and compensate for errors associated with a laser device which is generally stationary, and is designed for permanent application in a particular machine to constantly monitor the beam accuracy. The Muller et al. device, therefore, is not suited for use in a portable tool for aligning position errors of a laser beam at a rotating joint of an articulated laser beam delivery system.
Consequently, while laser alignment is increasingly becoming more and more critical with regard to various moveable laser beam delivery systems, heretofore there has not been a tool adapted for aligning both angular and translational position of a laser beam at a rotating joint of a delivery system which can easily be utilized without disassembly of a major part of the delivery system, and which is portable and applicable to a wide variety of delivery systems. Prior art alignment tools were limited either to translational or angular alignment, were unwieldy and impractical to use in applications including rotatable laser optics, were not reasonably portable and/or applicable to various delivery systems, or required disassembly and reassembly of a major portion of the delivery system.